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1.
The evidence derived from a genetical study of the plumage coloration of a stock of Indian Game bantams indicates that the three varieties differ one from the other in respect of the autosomal dominant gene 1. The Dark lacks the gene altogether, being ii in constitution, the Jubilee is heterozygous for it (Ii) and the White is homozygous (II). This gene is an incomplete dominant and affects the production of both black and red pigments, the black far more than the red. The degree of the density of the chestnut ground colour in the Dark and Jubilee varieties is determined by a number of modifying genes. It is possible by continued selection against this ground‐colour in the birds homozygous for the gene I to obtain a pure white bird, the white variety of the Indian (Cornish) Game.  相似文献   

2.
Dominant white coat colour (W) is a depigmentation syndrome, known in miscellaneous species. When homozygous in the horse (similar in mice), the mutation responsible for the white phenotype is lethal in a very early stage of gestation. It seems, that the action of the dominant white allele is not always fully penetrant, resulting occasionally in spotted look alike offspring. These horses resemble a coat colour pattern known as sabino spotting. So far, it is not known whether dominant white (W) and sabino spotting (S) share a common genetic background. In this study, a pedigree consisting of 87 horses segregating for dominant white (W) was used to genetically localize the horse (W)‐locus. Microsatellite ASB23 was found linked to (W), which allowed us to map dominant white to a region on horse chromosome 3q22. Tyrosine kinase receptor (KIT) was previously mapped to this same chromosome region (3q21–22). KIT and its ligand (KITLG) are responsible for the normal function of melanogenesis, haematopoiesis and gametogenesis. So far, sequence analysis of different KIT gene fragments did not lead to new polymorphisms, except for a SNP detected in KIT intron 3 (KITSNPIn3). Additional microsatellites from ECA3q (TKY353 and LEX7), together with KITSNPIn3 allowed us to state more precisely the (W)‐mutation. The positional results and comparative functional data strongly suggest that KIT encodes for the horse (W)‐locus.  相似文献   

3.
Fat-tailed sheep come in various colours—most are either brown (tan) or black. In some, most of the body is white with the tan or black colour restricted to the front portion of the body or to just around the eyes, muzzle and parts of the legs. The Karakul breed is important for the production of lamb skins of various colours for the fashion industry. As well as the black and tan colours there are Karakuls bred for grey or roan shades, a white colour or one of the numerous Sur shades. In the Sur shades, the base of the birthcoat fibre is one of a number of dark shades and the tip a lighter or white shade. All these colours and many others are the result of the interaction of various genes that determine the specifics of the coat colour of the sheep. A number of sets of nomenclature and symbols have been used to represent the various loci and their alleles that are involved. In the 1980s and 1990s, a standardised set, based closely on those of the mouse and other species was developed. Using this as the framework, the alleles of the Extension, Agouti, Brown, Spotting, Pigmented Head and Roan loci are described using fat-tailed sheep (mainly Damara, Karakul and Persian) as examples. Further discussion includes other types of “white markings,” the Ticking locus and the Sur loci.  相似文献   

4.
Females from a coloured inbred line of Leghorns (ii) were mated to three groups of males heterozygous for the dominant white gene (Ii). The parents transmitting the I gene to the three groups of males were respectively larger, smaller and of the same size as the parents transmitting the i gene. No differences were observed between the three types of crosses in the effect of colour genotype on body weight, providing no evidence for linkage between the dominant white locus and loci affecting body weight.

When comparisons were made between the colour genotype classes, pooled within full sib groups, the coloured genotype was larger in ten of the twelve test cross‐sex‐hatch combinations. Two of these differences, were statistically significant, but when the data were pooled over hatch, sex and test cross, no significant difference was found. The data thus offer meagre support for weight differences in favour of the coloured genotype, but the negative evidence of the pooled analysis raises considerable doubt that real differences in weights between the colour classes exist in these populations.

A similar comparison was made between the barred and non‐barred genotypes among the coloured female progeny in one test cross. The barred progeny were heavier in each hatch, in spite of the fact that the barring gene and sex chromosome were derived from the smaller grandparent. The differences were not statistically significant in either hatch or when the mean squares were pooled over hatches. It is concluded, therefore, that this experiment provides no evidence for any association between the barring locus and the genes for growth rate in this population.  相似文献   


5.
The aim of this study was to develop a non‐invasive procedure to stimulate ejaculation in median and small lizards for semen collection. After semen collection, we applied a battery of tests to assess the motility (wave and progressive), viability (eosin–nigrosin stain), morphology (normal/abnormal), sperm concentration and ejaculate number, seminal volume and colour. We obtained this fluid from all males of the four species of sceloporine lizards (n = 30) and one species of Mexican horned lizards (n = 7). We found that semen from all males had a liquid‐like consistency and a milky‐white appearance. Ejaculate volume and sperm concentration varied among the males and the species studied. We also observed that although the mobility, viability and normal sperm morphology showed a wide variability, their average value in each species was high. We conclude that “genital papilla pressure” was an efficient and non‐invasive semen obtaining method for small‐ and medium‐sized lizards that does not imply damage to donors and could be used in other lizard species.  相似文献   

6.
Vibrio tasmaniensis, Vibrio splendidus and Vibrio neptunius species were distributed worldwide and associated with aquaculture and have been reported as the cause of diseases in aquatic organisms. Polyphasic analyses for bacterial identification are not feasible for routine diagnostic because of the time involved. The aim of this study is to design three PCR primer sets that can assist with fast detection of these species. They were designed from the 16S ribosomal RNA gene, and PCR conditions were found. Each PCR test successfully identified all the tested strains of each target species. The combined specificity of V. tasmaniensis and V. splendidus primer sets offered the best coverage (86%) in terms of separating target organisms from other related species. The primer set of V. tasmaniensis showed a lower sensitivity limit (500 fg of DNA) than the V. splendidus set (1 pg) and both sets gave positive amplification using homogenized tissues from inoculated clams, with 102 and 104 cfu/g of clam, respectively. The primer set of V. neptunius was highly specific, showing only cross-reaction with V. parahaemolyticus species from 44 tested species. Its sensitivity limit was 100 pg of DNA. A small number of biochemical tests were proposed concurrently with the PCR to differentiate the cross-reacting bacteria. The time of detection of the three tested species was reduced and the further affected animals can be diagnosed in a rapid fraction of time. The detection of virulent strains of V. tasmaniensis pointed to the risk of mollusc culture outbreaks.  相似文献   

7.
Acacia species invest in condensed tannins (CT) and thorn defences among others. Plant defences are considered costly because they use resources that would otherwise be available for growth and reproduction. To reduce plant defence costs it has been argued that there are trade-offs between different types of defences. I tested for a trade-off between CT and thorn defences in Vachellia (Acacia) species. Thorn defences were expressed as thorn biomass, thorn density and thorn length. The relationship between defences was tested using Pearson correlation in addition to that with leaf area. My results support a trade-off between CT and thorn biomass and thorn density but not thorn length. Vachellia karroo (Acacia karroo) had high CT but low thorn biomass and thorn density, whereas V. gerrardii (A. gerrardii) had low CT but high thorn biomass and thorn density. Thorn length was positively correlated with CT and negatively related to thorn biomass and thorn density. Leaf area had a strong positive correlation with thorn biomass and thorn density, a weak negative relationship with CT, and a non-significant correlation with thorn length. I conclude that CT has a strong trade-off with thorn biomass and thorn density but not thorn length.  相似文献   

8.
《African Zoology》2013,48(1):112-117
The snake Psammophis schokari has a widespread distribution across North Africa, and in Morocco/Western Sahara is represented by three different morphotypes: striped, unicoloured and the Western-Sahara morph. ND4 mitochondrial DNA sequences from 28 specimens comprising 20 P. shokari, two P. aegyptius, one P. elegans, two P. sibilans, one P. condanarus and two outgroups were analysed. Within P. schokari we identified four genetic lineages (Morocco/Western Sahara, Mauritania, Algeria and Israel) with a genetic divergence ranging from 4-5%, less than that typically found between different species. Surprisingly, Moroccan/Western Sahara and Algerian lineages are the most divergent ones. This geographic substructuring may be due to severe climate changes in the Sahara desert between the Miocene and Pleistocene associated with expansion/contraction phases of this desert. Psammophis aegyptius is the sister-taxon of Psammophis schokari with a high level of genetic divergence between them (10.7%) supporting the recognition of P. aegyptius as a distinct species. The three Moroccan/Western Sahara colour morphotypes form one genetic lineage, indicating that colour pattern does not reflect a different phylogenetic history, and is probably an ecological adaptation to the local environment.  相似文献   

9.
The cerebral fasciculi (association, commissural and projection) pass through the cerebral white matter in organized groups connecting regions, hemispheres, gyri, areas and brain lobes to each other. The study can be done in vivo through diffusion tensor imaging (DTI) but presenting some technical problems. The post-mortem study by dissection allows to have a clearer view of its location, path and connections. In this work, we dissect, identify and compare the fasciculi of association of the white matter of the dorsolateral face of bovine hemispheres (Bos taurus), pig hemispheres (Sus scrofa domesticus) and rabbit hemispheres (Oryctolagus cuniculus), applying the Klingler´s technique. In 30 cerebral hemispheres (10 of each species, five right and five left), we applied the Klingler technique to identify and isolate the occipitofrontal fasciculus, uncinate fasciculus, inferior longitudinal fasciculus and superior longitudinal fasciculus; we established its location by fixing landmarks, and determined the difference in its length and width between the right and left hemispheres as well as between species using the statistical tests of t-student and one-way ANOVA. We identify the gyri, sulci and fasciculi of the dorsolateral surface of the cerebral hemispheres of the three species. We found statistically significant differences in several fasciculi between species principally in the occipitofrontal fasciculus. The preparation of the brains through the modified Klingler technique allowed a successful identification of the fascicules of association of the dorsolateral face of the cerebral hemispheres and the empowerment of these animal models for future research work in this field.  相似文献   

10.
The oriental white stork (Ciconia boyciana) is a threatened species, and their numbers are still in decline due to habitat loss and poaching. China is a breeding and main wintering area for this animal and in recent years some individuals have been found breeding in wintering areas and at some stopover sites. These new breeding colonies are an exciting sign, however, little is understood of the genetic structure of this species. Based on the analysis of a 463‐bp mitochondrial DNA (mtDNA) control region, we investigated the genetic structure and genetic diversity of 66 wild oriental white storks from a Chinese population. We analyzed the sequences of 66 storks obtained in this study and the data of 17 storks from a Japanese population. Thirty‐seven different haplotypes were detected among the 83 samples. An analysis of molecular variance showed a significant population subdivision between the two populations (FST= 0.316, P < 0.05). However, the phylogenetic analysis revealed that the samples from the different populations did not form separate clusters and that there were genetic exchanges between the two populations. Compared with the Japanese population, the Chinese population had a relatively higher genetic diversity with a haplotype diversity (hπ SD) of 0.953 ± 0.013 and a nucleotide diversity (π± SD) of 0.013 ± 0.007. The high haplotype diversity and low nucleotide diversity indicate that this population might be in a rapidly increasing period from a small effective population. A neighbor‐joining tree analysis indicated that genetic exchange had occurred between the newly arisen southern breeding colony and the northern breeding colony wintering in the middle and lower Yangtze River floodplain. These results have important implications for the conservation of the oriental white stork population in China.  相似文献   

11.
12.
In this paper we describe the use of polymorphic genes affecting coat colour as a tool in diversity studies of domestic animals. Although phenotypic data has been the main criteria for establishing different breeds, calculation of genetic distances between breeds is normally performed using noncoding microsatellite markers. As anticipated, MC1‐R (melanocyte stimulating hormone receptor) allele frequencies vary greatly between cattle breeds expressing different coat colours. In multicoloured breeds, like Icelandic cattle, a high frequency of the E+ allele appears to be essential for colour variation. Whereas black breeds have a high frequency of the dominant acting allele ED, entirely red breeds have no ED. Animals being homozygous for the defective allele e occurred frequently in some cattle breeds, indicating that the MC1‐R does not have crucial impact on animal physiology other than coat colour. The E+ and e alleles were observed in the closely related river buffalo as well. None of the breeds included in this study express the roan phenotype. Consequently, they were monomorphic at the MGF locus. As for the MC1‐R locus, a correlation to colour pattern was observed for two c‐kit alleles as well, confirming that selection of specific phenotypes strongly affect the allelic variation of underlying loci. Information on genes affecting the phenotype is therefore well suited for describing different breeds of livestock and, consequently, a practical tool in breed conservation.  相似文献   

13.
We investigated the effect of raising runt white sturgeon (Acipenser transmontanus) separately from dominant fish during the initial stages of grow-out in a commercial farm. Runt fish are poor-growers, have underdeveloped muscle mass, swim slowly and are more-frequently found at the top of the water column. The objective of the study was to describe the mortality and recovery rates (and their determinants) of white-sturgeon runts after separating them from dominant fish. Runt white sturgeon were stocked into twelve 2 m × 2 m rectangular tanks and graded periodically during a follow-up of 46–102 days. Overall mortality rates ranged from 0.3 to 7 dead fish per 1000 sturgeon-days at risk and overall recovery rates from 3.9 to 13.5 recovered fish per 1000 sturgeon-days at risk. Period-specific mortality and recovery rates increased over time. The period-specific mortality rates for all three periods were significantly higher for tanks of runts originating from grow-out tanks with high mortality (p-values: first period = 0.06; second period = 0.09; third period = 0.03), but were similar for tanks of runts of high- and low-mean initial weight. The period-specific recovery rates were significantly higher in runts originating from high-mortality grow-out tanks only for the third period (p = 0.05) but not the first and second periods (p-values = 0.33 and 0.25, respectively). Recovery rates were significantly higher in the higher-mean-weight runts tanks for the first and third period but not for the second (p-values: first period = 0.02; second period = 0.65; third period = 0.06). We concluded that the proportion of runts that recover during a 46–89 day period is substantial (16–58%); therefore, it might be worthwhile growing such fish separately in a fish farm for about three months. Financial analysis showed that this practice was profitable, if the value of white sturgeon fish for the farm exceeded $2.05 per kg.  相似文献   

14.
Rabies virus (RABV) does not persist in the environment as it is a very fragile agent. The primary hosts are mammalian species in the orders Carnivora and Chiroptera. Since the late 1980s, RABV has been isolated from non‐human primates, Callithrix jacchus (the white‐tufted marmoset), in four coastal states (Rio Grande do Norte, Ceará, Piauí and Pernambuco) in north‐eastern Brazil, where this species is indigenous. The original habitat of C. jacchus consisted of two Brazilian biomes, the Atlantic Forest and the Caatinga. However, these marmosets have since adapted to other ecosystems as a result of human activities. Between 1988 and 1989, RABV isolates were obtained from white‐tufted marmosets in the state of Rio Grande do Norte, but antigenic and genetic identification studies were not conducted at that time. In the following years, three additional states reported cases (Ceará, Piauí and Pernambuco). In two of these states (Ceará and Piauí), human cases of rabies transmitted by marmosets were reported. According to Brazilian Health Ministry data, at least 19 human cases in which this species was the source of infection were registered in between 1990 and 2016. Recent findings in laboratory tests of 12 rabid samples from humans and marmosets and the regional transmission among these animals for over 20 years, together with the gradual increase in the affected geographic area, support the concept of the emergence of a new RABV reservoir. Regional tourism, the wild animal trade and the cultural practice of maintaining these animals as pets, particularly in coastal regions, appear to be major risk factors for the increase in human cases. Additional epidemiological and ecological studies are required to better understand local disease dynamics and to identify ideal opportunities for prevention and control of this fatal infection.  相似文献   

15.
温带果园护土生草鼠茅草的腐解和养分释放   总被引:3,自引:0,他引:3  
鼠茅草是适合于温带果园的越年生护土生草,有助于防止水土流失,然而果农担心鼠茅草可能与果树争肥,不利于果树生产。本研究在青岛地区温湿气候条件下测试鼠茅草的腐烂分解及养分释放特征。2012年6月底采集枯死鼠茅草,将其埋在10 cm深的土壤中,使土壤含水量分别稳定在田间持水量的65%,75%和85%,7-10月份每隔10 d抽检其腐解程度和碳、氮、磷、钾元素的释放速率。结果表明,鼠茅草的腐烂分解是比较快的,自初夏枯死后经80 d大约分解30%;伴随鼠茅草的腐烂,碳、氮、磷和钾会释放出来,快速释放期集中在前20-40 d,钾的释放速度最快,其次为磷,碳、氮的释放速度较慢;土壤含水量影响鼠茅草的腐解过程,当土壤含水量由65%田间持水量提高至85%时,鼠茅草的腐解和养分释放加快。据此可断,7-10月是鼠茅草分解的主要时期,可为果树生长提供营养而非争夺养分。在青岛等温湿地区,以鼠茅草作为果园护土生草是可行的,它们同苹果等落叶果树在养分利用上可形成互补关系,有益于果园的养分循环和持续生产。  相似文献   

16.
《African Zoology》2013,48(1):88-94
Four lacertid lizards, Pedioplanis laticeps, P. lineo-ocellata, Meroles knoxii and Nucras tessellata, occur sympatrically on the arid plains of the Tankwa Karoo Basin in South Africa. The aim of this study was to determine whether the four species are spatially separated in terms of the microhabitat each species occupies, allowing them to occur in sympatry in this structurally simple system with a limited number of potential niches. The habitat preferences of the four species were investigated on the farm Gansfontein in the southwestern parts of the Tankwa Karoo Basin. The area was surveyed by walking transects through different habitat types and recording all active lizards. For each lizard observed, the species was identified and a photograph was taken of its microhabitat. At the end of the sampling period the microhabitats in which lizards were found were sorted into distinct types on the basis of substrate composition. During the survey, only one individual of N. tessellata was recorded, but sample sizes for the other three species were sufficiently large to provide a clear perspective of habitat segregation among the three species. The results showed that the three species are spatially separated at the study site, with P. lineo-ocellata being restricted to rocky areas, P. laticeps preferring gravel substrates and M. knoxii frequenting sandy areas. Although only anecdotal information is available, all indications are that the observed spatial separation of the three species is mainly the result of historical adaptation to the different substrate types.  相似文献   

17.
1. An experiment was conducted with laying hens to determine to what extent sweet white lupins (Lupinus albus, cv Buttercup) could be used as a protein source in their diets.

2. Twenty five individually caged 20 week‐old Hisex laying hens were used per treatment. The hens were housed in a convection house for the duration of the study which lasted 52 weeks. Two diets were formulated, one containing 300 g sweet lupins/kg and the other containing sunflower oil cake and fish meal as protein sources. These diets were blended to obtain seven diets with lupin inclusion rates of 0, 50, 100, 150, 200, 250 and 300 g/k.

3. Results indicated that up to 300 g lupins/kg diet can be fed to Hisex laying hens without a significant effect on egg production, egg mass, efficiency of food utilisation, egg shell thickness, Haugh units or yolk colour. Food intake was however, significantly (P<0.05) positively correlated with lupin inclusion rates.  相似文献   


18.
In order to evaluate embryo production in Morada Nova (white variety) ewes superovulated with porcine follicle-stimulating hormone, 20 cycling ewes were used as embryo donors and allocated into two groups according to age: group 1 (ewes aged 1–2 years; n = 9) or group 2 (ewes aged 3–4 years; n = 11). Embryo recovery was performed by laparotomy 5–6 days after oestrus. The evaluation of embryos was made under stereomicroscope according to International Embryo Transfer Society rules. The overall recovery rate was 64.6% (5.0 ±  0.7 structures per ewe) and 86.3% of the recovered structures were fertilized. Group 1 was superior (p < 0.05) to group 2 according to recovered (6.6 ±  0.9 vs 3.6 ±  0.8) and fertilized structures (5.6 ±  1.1 vs. 3.5 ±  0.7) per ewe. In conclusion, the ovarian response and the embryo production in Morada Nova (white variety) sheep subjected to a standard superovulation treatment were considered satisfactory. In addition, the use of multiple ovulation and embryo transfer in younger ewes (≤ 2 years old) of this sheep breed appears to be an efficient tool to accelerate the preservation of the Morada Nova (white variety) breed, since younger ewes are as responsive as older ones.  相似文献   

19.
20.
The alleviation of pain and prevention of suffering are key aspects of animal welfare. Unfortunately, analgesic drugs are not available for all species. White rhinoceros (Ceratotherium simum ), representing one of such species, which survive poaching attempts inflicted with severe facial injuries and gunshot wounds, nonetheless require analgesic support. To improve treatment conditions, this study explored the use of carprofen for the treatment of pain and inflammation in white rhinoceros. The pharmacokinetics of 1 mg/kg intramuscular carprofen was evaluated in six healthy white rhinoceros. The half‐life of λz and mean residence time was 105.71 ± 15.67 and 155.01 ± 22.46 hr, respectively. The area under the curve and the maximum carprofen concentration were 904.61 ± 110.78 μg ml?1 hr?1 and 5.77 ± 0.63 μg/ml, respectively. Plasma TXB 2 inhibition demonstrated anti‐inflammatory properties and indicated that carprofen may be effective for a minimum of 48 hr in most animals. With its long half‐life further indicating that a single dose could be effective for several days, we suggest that carprofen may be a useful drug for the treatment of white rhinoceros.  相似文献   

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